Sofirn C8F host. 21700 C8F Available

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Drontti
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BlueSwordM wrote:
It won’t probably thermal throttle on the 500 lumen mode, and it will step down on the timer, but you will be able to get the 500 lumen mode back up.

Is this about SP33 or C8F? If both can manage constant 500 lumen, then added max lumens on C8F feel tempting, even though I’d need to pay quite alot more for it than SP33 (damn taxes on 22€+ shipments)

BlueSwordM
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The SP33. The C8F can’t actually manage more than 100 lumens of constant brightness, so the 500 lumen mode on the C8F will go down by quite a bit as the battery drains.

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

DB Custom
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The SP31A would only be using Buck mode if 2 CR123A’s are installed. They have low capacity compared to a high capacity 18650 so using those half cell sized batteries would be sort of silly. Am I missing something?

BlueSwordM
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No. The SP31A uses an XPL2, which has a very low forward voltage compared to the XPL, and especially XPL-HI.

On turbo at 1000 lumens, it’ll stay in regulation until the cell voltage reaches 3,7V using most buck drivers with a drop out voltage of 0,5V.

On the 350 lumen mode, it’ll basically stay in regulation down to 3,3V, where most of the useful energy of the cell would be used, about 2,5Ah out of a 30Q, so almost all of the capacity out of the cell before internal resistance goes up, so the 350 lumen mode will stay regulated up until the cell is almost empty.

That’s also the reason the XPL2 is such a monster: it can draw a ton of current from a cell since its forward voltage is very low.

Using a very low voltage LED like the XPL2, Nichia 219C 90CRI, LH351D 90CRI, and E21A array are probably the only LEDs in which using a buck driver is actually very useful with a single 18650.

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

DB Custom
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Have used dozens of those emitters, haven’t noticed them having such a low Vf, probably because I don’t give em the chance… Wink

JasonWW
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Bottom line is:

The highest sustainable output plus the longest runtimes will always be with a bigger light. It can dissipate heat better and usually has bigger batteries.

Generally speaking, go with the biggest light you can.

Texas Ace Lumen Tube calibrated with Maukka lights

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vinte77
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So for those of you that are planning to buy a 21700 C8F host version and can’t figure out which driver to use. I can recommend Lexel’s narsilm driver. I had a 22mm driver that I grinded down until it fit. There’s plenty of room on the topside ring of the driver that it sits on the driver shelf without any of the driver components touching the shelf. On the bottomside of the driver, I added 3 solder blobs placed on the ring high enough that it just touches the retainer ring (I can post a picture later if people want to see it). Just remember to not put to much pressure when screwing in the driver retainer ring so that it cracks a 7135 chip (ask me how I know this).

Only problem with my light is that I accidentally ripped off one of the switch wires from the the soldering pad on the driver so now I need to try and fix it later. I emailed Lexel and he wrote me back how to get around it, so hopefully I can salvage the situation or if not I guess I’ll order another driver from Lexel.

The other problem I ran into was that I couldn’t figure out how to wire the stock switch to the driver. Luckily I had one of Lexel’s switch boards, it’s much easier to wire the switch when the solder pads are labeled. After putting the switchboard together, I realized that the leds weren’t bright enough for me (since the rubber boot is a dark color, anyone know if there are clear replacement boots that fit?). So I when I have more time I’ll go back adjust that as well.

the4ds9
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I received mine, took nearly one month but Sofirn service was superb. Flashlight is a thing of beauty. Better than my former favorite, the original spec (3450 lumen) Jetbeam TH20. The 21700 battery combined with three deep-reflector well LED is so much better! Cool

I had a chance to go Turbo with the EFEST from Battery Junction. “Overwhelming force” is the thought that describes it. I have used the Jetbeam TH20 a lot with fully charged Sony VTC5A and Sanyo UR18650NSX. This Sofirn C8F 21700 with the EFEST is remarkably brighter. My dark, cavernous kitchen is lit up entirely, and into the backyard. It feels on par with the old Thrunite soda can lights from the year 2014 in terms of shock and awe feeling. Very bright. Perfect for pest control. Wish I had this over the Jetbeam TH20 when I was pest controlling food moths. This is just plain brighter, for longer, and covers a greater area. Thumbs Up

JasonWW
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vinte77 wrote:
anyone know if there are clear replacement boots that fit?

What size is it?

Kaidomain carries a lot of boots.

Texas Ace Lumen Tube calibrated with Maukka lights

Click this to go to signature links.

johnkey68
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vinte77 wrote:
So for those of you that are planning to buy a 21700 C8F host version and can’t figure out which driver to use.

Today answered :

Thank you friend
Yes, a driver for C8F-21700 is available, i will do a new link of it

Agro
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Any news about the flat tail?…

ZozzV6
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Nothing yet. But I got my “thank you” C8F pack from Sofirn yesterday. It is a full pack 21700 version with battery, charger, 18650 tube. It has some issues but I contacted them and they are on it. Also as the low output problem of some lights. At first I also measured 2550 lumens with 18650 battery at first try but it was not completely full. Now with fully charged Sofirn 21700 it makes 3102 lumens. Temp regulation works fine. I measured 54°C on the head maximum and it stayed there while the light was adjusting output slowly down. My only negative now is the ramp characteristic. It maybe linear to current but not linear to the eye. The low side going up fast but the upper half barely changing. If they make an exponential curve to that like Narsil it will be a very good firmware.
Also like how they solved the two switch operation. It remembers the level and also if you leaved on or off with side switch. So when you press off and then On the tailcap it came back at any level you left or in a standby/off state.

So if have some issues. Don’t worry! It will be solved

JasonWW
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I still haven’t got mine. It’s almost a month now. I hope it didn’t get lost. The last tracking date was Sept 2nd in China and then nothing.

Oh well, hopefully it will just show up. Lol

Texas Ace Lumen Tube calibrated with Maukka lights

Click this to go to signature links.

DB Custom
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I used my 21700 C8 last night on my Thursday night walk, the Samsung LH351D in 5000K 80 CRI looked really good in the night and the power level was really good as well. Enjoyed it a lot, sure to be a favorite among my user group and will make it harder to decide which light to grab. Wink

Di_Joker
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Has anyone tested the temperature at different brightness at room temperature?
I have a C8F 18650: in 1500Lm its temperature is less than 55C, at 800-1000Lm and turbo 2500Lm after 20 minutes at 58C, at 650LM in 25minutes 55C. It turns out the most effective mode of 1500Lm and 2500Lm.
And how does the C8F 21700 behave?

Sorry for my poor english.

ZozzV6
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I only tried turbo stepdown yet on my 21700 version. It stabilizing at 54°C

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Made a test on the next level under turbo. The next level after that is about 700 lumens so I think there is no stepdown from there.

P33
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Does anyone know if Sofirn will have the new C8F hosts without branding on offer? I saw that other C8s are available on their store aliexpress page without engravings and that would make that host much more appealing Wink

contactcr
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a few of us have already received the hosts and they did not have any branding on them. However, no promises in what you will receive.

P33
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Great news! Time to build my first torch then Big Smile

DB Custom
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Remember that you need a driver that takes an e-switch. The e-switch in the Sofirn C8 host is mounted on a board and held in with a threaded retaining ring, it’s all installed when you get it with the wires sitting loose in the head. But you need a 21mm driver that takes an e-switch. They provide the copper MCPCB that mates up to the reflector, you’ll need to reflow emitter onto it… XP footprint.

And yes, my host is unbranded.

P33
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Yes, I did gather all that information, reflowing emiters onto the MCPCB would defo be quite challenging so it might not be stupid to ask someone for help with this later.
May I ask what drivers did you get for this build?

Di_Joker
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I apologize. At full 18650 1500Lm almost does not differ from the turbo, heating more than 800-1000Lm.

Sorry for my poor english.

DB Custom
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I built an Anduril driver with an ATTiny85 MCU and FET+1 set up, used a 17mm driver board from Wight, the A17Hybrid-S, and adapted it up to the 21mm opening.

Brainsick67
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Just got an update from Amazon US..it says it will be here Thurday..YAY

I'm ThatCrazyFlashaholic 67

the4ds9
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Brainsick67 wrote:
Just got an update from Amazon US..it says it will be here Thurday..YAY
Thumbs Up

Being budget-minded, instead of purchasing a 3rd 21700 cell, I will use the 18650 I already have.

KawiBoy1428
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LEDtec wrote:
Yesterday I received my C8F 21700,
I measured only 2140 lumens, and only 6.07A at the tailcap.
Moreover when I step in turbo mode the brightness starts at about 1200 lumens and then slowly, in about 8/10 sec, it goes up to 2140 lumens, I do not think this is normal?

Maybe a stock of faulty drivers ??


Yep, I’m glad I found this, I thought WTF is going on? Facepalm The driver is a POS! The lumin output in all modes creeps up and the higher modes even more slowly, as do the amp readings. Took forever to get the highest amp/lumin readings? Best I got was 2440lm. at Turbo and 6.43amps, using a 30T with an 8awg jumper wire, not the cap. With the cap it was like 2100-2200lm. Crying

But I bought it to tear it apart… so meh…Truly love the build quality, it is outstanding! Thumbs Up

KB1428 “Live Life WOT

Brainsick67
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I got mine also..when u hit Turbo..it creeps up to turbo like the post above..im unsure the lumen measument.

I'm ThatCrazyFlashaholic 67

ZozzV6
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Mine with the stock Sofirn battery made 3100 lumens. I also noticed that it is creeping up. And mine draws 8,5A
I ope Sofirn take a look at the drivers. I told them there are some issues.

Brainsick67
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Hmmmm..how do u check the amps?

I'm ThatCrazyFlashaholic 67

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